Field of the Invention
The present invention relates to an image pickup apparatus equipped with a display section that displays an image to be photographed, and the method of controlling the image pickup apparatus.
Description of the Related Art
A compact digital camera and a non-reflex camera (lens interchangeable camera without a mirror box) are each equipped with a small-sized electronic viewfinder (EVF) for checking an object to be photographed, differently from a single-lens reflex camera. The camera of this type does not need to be equipped with a mirror box by employing the EVF, and hence it is possible to realize reduction of the size and weight of the apparatus body. On the other hand, a certain time period is required to perform image processing for displaying an image to be photographed on the EVF. Therefore, there is a problem that a time difference between an image displayed on the EVF and an object image to be actually photographed is generated, which makes it difficult to photograph the object at a moment intended by the photographer.
Conventionally, most of users of compact digital cameras are not professional cameramen, and hence the above-mentioned display delay in the EVF has not been considered as a serious problem.
However, in recent years, products for amateurs having high awareness of photographing techniques or professional cameramen, represented by a high-class compact camera and a mirrorless camera, have been increased in number, and the problem of display delay cannot be ignored.
To solve the above-mentioned problem of display delay, there has been proposed a technique for reading images from an image pickup device, starting with an object area observed by a user (observed area), and sequentially displaying the images on the EVF starting with an image read from the observed area. Further, there have been proposed a technique for changing the order of reading images and the order of displaying images on the EVF, and further, a technique for omitting image processing with respect to images other than the image read from the observed area (see e.g. Japanese Patent Laid-Open Publication No. 2006-60496).
However, although the above-mentioned technique for reading an image from the observed area first and displaying the image read from the observed area first makes it possible to reduce the time of display delay with respect to the observed area, it requires a dedicated image pickup device which can perform a special reading operation, and a dedicated EVF which can display images in a special order adapted to the dedicated image pickup device. Further, the technique for omitting image processing with respect to images other than the image read from the observed area has a problem that image quality of the whole EVF display image is degraded due to omission of image processing, and if the observed area is in the vicinity of the center of the displayed image, distortion of the image due to the lens becomes noticeable in the peripheral part of the image.